Question

Beginning with the flow phase, arrange the biochemical processes in the order in which they occur during the menstrual cycle.

Answer 1

Menstrual cycle is a complex cycle that consists of several processes. Order of occurrence of steps in menstrual cycle are as follows:
1. High progesterone levels maintain the endometrium lining of the uterus.
2. Endometrium lining breaks down and low levels of estrogen stimulate the pituitary to release FSH and LH.
3. FSH and LH stimulates the follicles to develop and the oocyte to produce estrogen.
4. Rising estrogen levels suppress FSH production and development of other follicles.
5. A spike in LH causes follicle to rupture.
6. A breakdown of corpus luteum causes progesterone level to drop.

Answer 2

The right order is:

6. High progesterone levels ...

4. The endometrium lining breaks down ...

1. FSH and LH stimulate...

5. Rising estrogen levels suppress FSH production ...

3. A spike in LH causes follicle to rupture.

2. A breakdown of corpus luteum ...

THE MENSTRUAL CYCLE IS DIVIDED INTO 2 PHASES:

Phase 1: the estrogenic or follicular phase (14 days)

The ovarian follicules each house an egg. They continue to grow thanks to the hormone FSH (follicle stimulating hormone) secreted by the pituitary gland, a gland at the base of the brain. But in the end, only one follicle matures. The others will then disappear.

The ovaries produce estrogen that will allow the endometrium to thicken to accommodate an egg in case of fertilization.

The estrogen level gradually increases in the blood and triggers the sudden release of luteinizing hormone (LH), which has been secreted and stored by the pituitary gland. Under the action of this hormone, the dominant follicle breaks and delivers an egg: it is the moment of ovulation.

The oocyte initiates the descent of the fallopian tube to the uterus for 3 or 4 days. It is fecundable for about 24 hours. Then, and if he has not met sperm, he degenerates.

Phase 2: the progesterone or luteal phase

The second phase of the menstrual cycle begins after ovulation and lasts 2 weeks.

Under the action of the LH, the follicle that released the egg turns into a yellow body. This temporary cell structure produces estrogen and a large amount of progesterone. This hormone acts on the thickening of the uterine lining, which is enriched with nutrients.

Progesterone production peaks about 8 days after ovulation and then declines as the pituitary stops secreting LH. The corpus luteum deteriorates around the 23rd day, until the 28th day. This also causes a drop in estrogen levels.

This hormonal variation influences the state of the endometrium. As it does not receive so much blood and oxygen, the upper wall of the mucosa gradually degenerates and is evacuated by the vagina in the form of bleeding, what is called menstruations.